Please do everybody a favor here. If your going to post prices where there's a cash price and a credit price, post the cash price. Why the cash price you ask? Because it's lower. That's the whole reason behind GasBuddy.
Then use the notes field saying how much more the credit price is. For example the Chevron at 148th Ave NE and NE 8th Street in Bellevue, I have placed "ADD 10¢ FOR CREDIT" (to get the ¢ symbol, hold down the ALT key and type 155, then let go of ALT key).
This is outlined in the FAQ. http://www.seattlegasprices.com/faq.aspx#16 If you're not able to use the notes field witha mobile device, then try accessing it from a PC/Desk Top.